1. Field of the Invention
The present invention relates to a sheath device for an endoscope, which is fitted over an insert tube of the endoscope that is inserted into a hollow organ of the patient's body, the sheath device being designed so that a portion thereof which comes into contact with mucus and mucous membrane in a hollow organ of the patient's body can be disposed of after use for one endoscopic procedure. The present invention also relates to a fluid conduit connecting structure for use in the sheath device described above.
2. Description of the Prior Art
To prevent the transmission of bacteria or viruses from one patient to another through an endoscope, it is the most effective way to arrange an endoscope such that a portion thereof which comes into contact with mucus and mucous membranes in a hollow organ of the patient's body can be disposed of after use during one endoscopic procedure.
Among various portions that comprise an endoscope, those which come into contact with mucus and mucous membranes in a hollow organ of the patient's body include the outer surface of the insert tube and channels such as forceps suction, air and water channels. Accordingly, a typical conventional sheath device for an endoscope is designed so that a sheath which covers the insert tube and channels are disposable as one set.
However, control valves for control of the supply of air and water are generally provided in the control part of an endoscope. It is therefore necessary to disconnect channels, for example, air and water channels, from the control valves in the endoscope each time the endoscope has been used.
In this type of conventional sheath device for an endoscope, the channels that are provided in the sheath device are individually connected to the respective control valves in the endoscope. Accordingly, each channel must be disconnected from the corresponding control valve when the sheath device is to be removed from the endoscope (see U.S. Pat. No. 4,646,722).
Thus, a complicated and troublesome operation is required to connect and disconnect each channel, and it is exceedingly difficult to handle the sheath device. In consequence, a great deal of time is needed to remove the sheath device after use, and there is a danger that the endoscope may be contaminated during the removal of the sheath device.
In addition, since the channels must be adapted to be detachable with respect to the control valves, it is difficult to employ a valve mechanism which is commonly used in endoscopes, and a special valve mechanism must be prepared.
The connection of each pair of channels is generally effected through a metal pipe, for example, which is disposed along the axis of the channels which are connected together in a straight-line form. Accordingly, it is necessary to ensure a long space for the connection of the channels. As a result, the length of the control part of the endoscope increases, and hence the operability deteriorates.
One type of conventional sheath device for an endoscope is arranged such that the sheath is inflated with air when the insert tube of the endoscope is inserted into and removed from the sheath in order to enable the insert tube to be smoothly inserted and removed. In this type of sheath device, the insert tube of the endoscope is inserted into and removed from the sheath through a packing which is provided in an opening at the proximal end of the sheath. In the prior art, the packing is fixedly provided in the opening at the proximal end of the sheath.
In consequence, when the insert tube of the endoscope bends, the packing which is pushed by the insert tube is deformed to produce a gap through which air leaks out. When the insert tube of the endoscope, which is in a state where no turning force is applied thereto, is turned about its axis, a gap is produced between the packing and the insert tube, resulting in air leaking out through the gap.
If air leaks out from the sheath, the sheath deflates; in such a case, not only the insert tube of the endoscope is caught in the sheath and cannot be smoothly inserted or removed, but also the sheath may be broken.